Problems with hypercalls

[mulyadi.santosa@gmail.com (Mulyadi Santosa)]

Hi...

On Wed, Jun 8, 2011 at 21:54, emilie lefebvre <tricheurs@hotmail.fr> wrote:
>
> This is my function :
>
> static spinlock_t xgr_learn_lock = SPIN_LOCK_UNLOCKED;
> static int piga_seq_cpt = 1;
>
> /*
> * Function called for each systemcall (Hook SELinux avc function)
> */
> int piga_control(u32 ssid, ...., struct av_decision * avd) {
>
> /*
> * Here my hypercall work but block my vm with this error :
> * ?????????????? " BUG: scheduling while atomic ... "
> */
>
> spin_lock_bh(&xgr_learn_lock);
> ? if ( in_atomic())
> ?????????? kvm_hypercall2 ( 6, (unsigned long)2 ,(unsigned
> long)piga_seq_cpt);

AFAIK, anything that trigger context switching, usually trigger
rescheduling too....or in other word, does blocking. Therefore,
grabbing lock must be avoided IMHO

> ? spin_unlock_bh(&xgr_learn_lock);
>
> ?if (piga_on == 1) {
> /*
> * Here my hypercall make a kernel panic with this error:
> * ??????????? " divide error: 0000 [#1] SMP"
> */
> ??????????????? spin_lock_bh(&xgr_learn_lock);
> ??????????????? set_current_state(TASK_UNINTERRUPTIBLE);

wait wait, why setting as uninterruptible?

> ??????????????? kvm_hypercall2 ( 6, (unsigned long)2 ,(unsigned
> long)piga_seq_cpt);
> ??????????????? set_current_state(TASK_RUNNING);
> ??????????????? spin_lock_bh(&xgr_learn_lock);
> }
> }
>
>
>
>
>
>> Date: Wed, 8 Jun 2011 15:52:33 +0530
>> Subject: Re: Problems with hypercalls
>> From: fs.rajat at gmail.com
>> To: mulyadi.santosa at gmail.com
>> CC: tricheurs at hotmail.fr; kernelnewbies at kernelnewbies.org
>>
>> are you doing 64bit devision on 32 bit arch? If that is the case,
>> do_div is worth considering.
>>
>> On Wed, Jun 8, 2011 at 3:25 PM, Mulyadi Santosa
>> <mulyadi.santosa@gmail.com> wrote:
>> > On Tue, Jun 7, 2011 at 15:39, emilie lefebvre <tricheurs@hotmail.fr>
>> > wrote:
>> >> "divide error: 0000 [#1] SMP
>> >> ...
>> >> ?[<ffffffff813f8cdd>] panic+0x78/0x137
>> >> ?[<ffffffff813fcb94>] oops_end+0xe4/0x100
>> >> ?[<ffffffff8101021b>] die+0x5b/0x90
>> >> ?[<ffffffff813fc444>] do_trap+0xc4/0x160
>> >> ?[<ffffffff8100df2f>] do_divide_error+0x8f/0xb0
>> >> ?[<ffffffff811f974c>] ? my_function+0xdc/0xe70 "
>> >>
>> >> Could you have any suggestions ?
>> >
>> > Could you show us your code? perhaps by pasting them somewhere?
>> >
>> > >From what I guess, sounds like your code did some math (directly or
>> > indirectly) that fiddle with floating point numbers?
>> >
>> >
>> > --
>> > regards,
>> >
>> > Mulyadi Santosa
>> > Freelance Linux trainer and consultant
>> >
>> > blog: the-hydra.blogspot.com
>> > training: mulyaditraining.blogspot.com
>> >
>> > _______________________________________________
>> > Kernelnewbies mailing list
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>> >
>>
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>



-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com